WarSampo – Finnish WW2 on the Semantic Web


Date coverage: 1939 - 1945 Website Contact

Digital Humanities Linked Data Knowledge Graph Persons data

“WarSampo – Finnish World War 2 on the Semantic Web” [1] is a semantic portal and Linked Open Data infrastructure that promotes peace by publishing reliable data about the price of the war for everybody to learn. The system is also used for Digital Humanities research. According to Georg Wilhelm Friedrich Hegel “we learn from history that we learn nothing from history”.  WarSampo tries to show that he was wrong!

Reassembling the lives of soldiers

The key idea of WarSampo is to reassemble automatically the life stories of the soldiers using linked data from multiple (some 20) data sources. A typical user of the WarSampo seeks information about her/his deceased relatives in the war.  WarSampo has become a popular national  web service that has had by now 860 000 distinct users, which is a fair number in a small country like Finland for a research prototype.

Using the system

The WarSampo knowledge graph [2] contains an ontology of WW2 events, based on an extended CIDOC CRM data model, and information about the 95 000 deaths of all Finnish soldiers killed in action, activities of nearly 10 000 military units of war interlinked with, e.g., some 26 000 original war diaries at the National Archives, thousands of magazine articles of memoirs of the war, and 160 000 authentic photos from the fronts. Given a person of interest, this wealth of information can be provided to the information seeker through automatically generated “homepages” for the dead as well as for some 5000 well-known soldiers who survived. There are also homepages for related entities of interest, such as tens of thousands of places, military units, events, etc. with visualizations on, e.g.,  historical maps and timelines.

WarSampo publishes harmonized data as a Linked Open Data (LOD) service (a SPARQL endpoint) that contains 14 million triples. Application demonstrators are built on top of the LOD service that provide different perspectives to war history, for both historians and the public. The data covers the Winter War 1939-1940 against the Soviet attack, the Continuation War 1941-1944 where the occupied areas of the Winter War were temporarily regained, and the Lapland War 1944-1945, where the Finns pushed the German troops away from Lapland.

The WarSampo knowledge graph is an official part of the international Linked Open Data Cloud, and the portal is a member of the national “Sampo series” of semantic web portals in use, based on the “Sampo” model:


The first version of WarSampo was published in 2015. After that  the system has been extend with additional application perspectives related to, e.g., military cemeteries and Finnish prisoners of war in the Soviet Union.

WarSampo was awarded the Open Data prize in the 2017 LODLAM Challenge in Venice.

WarSampo was designed and implemented by the Semantic Computing Research Group (SeCo) at the Aalto University and University of Helsinki (Helsinki Centre for Digital Humanities HELDIG), based on the data and collaborations of the National Archives of Finland, Finnish Defense Forces, and other organizations.

Links for more information

Video about WarSampo: https://vimeo.com/212249404

WarSampo portal: https://www.sotasampo.fi/en/

WarSampo LOD service: https://www.ldf.fi/dataset/warsa

Project homepage: https://seco.cs.aalto.fi/projects/sotasampo/en/



[1] Eero Hyvönen, Erkki Heino, Petri Leskinen, Esko Ikkala, Mikko Koho, Minna Tamper, Jouni Tuominen and Eetu Mäkelä: WarSampo Data Service and Semantic Portal for Publishing Linked Open Data about the Second World War History. The Semantic Web – Latest Advances and New Domains (ESWC 2016), pp. 758-773, Springer-Verlag, 2016.


[2] Mikko Koho, Esko Ikkala, Petri Leskinen, Minna Tamper, Jouni Tuominen and Eero Hyvönen: WarSampo Knowledge Graph: Finland in the Second World War as Linked Open Data. Semantic Web – Interoperability, Usability, Applicability, vol. 12, no. 2, pp. 265-278, 2021.


Project partners

Public datasets

WarSampo - Finnish WW2 on the Semantic Web

Karelian map names 1922-44, Finnish municipalities 1939-44, War Cemeteries in Finland, War Diaries, Finnish Winter War, Casualties during the Finnish wars 1939–1945, Wartime Events, Persons of World War 2 in Finland, Military Units, World War 2 in Finland, Kansa taisteli magazines, Wartime Photographs

License: CC BY